With the increased rate of success of ophthalmic surgery, the need has grown for surgical devices and methods which further enhance surgical techniques. With the advent of varied and different surgical techniques, new devices and methods have been advocated and new successes have been recorded. Specifically, the need to enhance the methods and procedures for performing the anterior capsulectomy during extracapsular surgery have become critical to the success of the surgery. Numerous methods are currently used and numerous apparatus are currently employed.
Many surgical and diagnostic procedures are currently being performed manually. In many instances, the clinician has difficulty performing the procedure or evaluating the condition using the manual method.
Automation of the device goes far beyond the use of electromechanical or other energy forms to drive the instrument. Automation implies the development of a more sophisticated device that significantly improves the procedure as it is currently performed.
The development of an automated device requires the use of new techniques, and not merely using a new device the old way. Significant patient benefits will result by enabling the clinician to be more effective and efficient. This includes: reduced trauma, better postoperative rehabilitation, and more quantitative results.
The anterior capsule is a cellophane-like membrane covering the anterior surface of the lens. It is continuous with the posterior capsule, a cellophane-like membrane behind the lens. The human lens is encapsulated by this membrane. In order for a cataract (opacified lens) to be removed in an extracapsular extraction procedure, the anterior capsule must be opened to allow for instrumentation to enter "the bag" and removal of the nucleus and cortical material. Various techniques and principles have been devised to cut or tear the anterior capsule. For example, some well known techniques include the "Christmas tree," the "Beer-can," and various modifications of these techniques. An excellent review of the methods and complications can be found in Phacoemulsification and Asperation of Cataracts, J. M. Emery and J. H. Little, Eds., Chapter 10, (1979), C. V. Mosby Co.
The anterior capsulectomy is generally recognized as the most difficult step in the cataract procedure. Numerous articles have appeared in Ocular Surgical News and Ophthalmology Times on the anterior capsulectomy procedure. Many surgeons have tremendous problems with the capsulectomy procedure even through they are quite proficient in the other steps in the procedure.
A poorly performed anterior capsulectomy significantly increases the difficulty in performing the subsequent steps in the procedure and the probability of operative complications. Complications resulting from a poor capsulectomy include: zonular stress with subsequent breakage of the posterior capsule, difficulty in nucleus expression, and large capsular tags preventing efficient cortical removal including increased operative time and probability of vitreous loss. A poor capsulectomy also prevents placement of an intraocular lens (IOL) in the capsular bag due to ill-defined capsular structures. Many journal articles, some referenced herein, substantiate the difficulty in performing the procedures and the ensuing complications from a poorly performed technique. The articles also suggests surgical techniques to improve the results and reduce the difficulty in the subsequent steps.
As a result of the difficulties and complications cited, a definitive need exits for a device and technique to perform an efficient, effective, and efficacious anterior capsulectomy. Such a device should simplify the procedure and enable the surgeon to perform the capsulectomy, and the subsequent steps, more quickly and effectively.
Some of these prior used methods include manual and mechanical techniques for severing the anterior lens capsule of the eye to perform the capsulectomy. For example, a mechanical device was disclosed by Henry M. Clayman and Jean-Marie Parel in the American Intra-Ocular Implant Society Journal, Volume 10, Fall 1984, pp. 479-482. The Clayman/Parel paper, entitled "The Capusule Coupeur for Automated Anterior Capsulectomy," describes a mechanical automated anterior capsulectomy device. The Clayman/Parel device operated from a power source and provided a rotating cutting tip. The rotating cutting tip extended from the end of a tube and rotated orthogonal to the center axis of the tube. The cutting edge caused the incision of the anterior lens capsule of the eye.
Additional devices are known for performing the capsulectomy. For example, Sharp Point, Inc. has a manual device which utilizes a rigid rod with a freely rotating cutting member for cutting the eye. As the cutting member at the end of the rod is moved in a circular path across the tissue, the cutting edge of the "nail-like" cutting member cuts the lens of the eye along the path traversed. Other manual devices are known in the art, for example, cystotomes and gauge vent needles. Also, an ultrasonic driven uptotome is known in the art.
In all of the prior known devices, it is difficult to cleanly cut the capsule without leaving residual "tags" or tears in the capsule. Also, prior known devices either cause sufficient drag on the capsule to rock the nucleus of the lens or to place stress on the zonular structure. All of these problems tend to create undesirable foundations for intraocular lens placement or other surgical complications.
It is, therefore, a feature of the present invention to provide a capsulectomy apparatus which facilitates a continuous smooth, curvilinear cut.
Another feature of the present invention is to provide a capsulectomy apparatus which does not rock the nucleus of the lens.
Yet another feature of the present invention is to provide a capsulectomy apparatus for facilitating a continuous, smooth, curvilinear cut of the anterior lens capsule while reducing zonular stress and ultimately eliminating zonular dialysis.
Still another feature of the present invention is to provide a capsulectomy apparatus which provides a cleanly cut capsule.
Yet still another feature of the present invention is to provide a capsulectomy apparatus that eliminates residual tags of the anterior capsule.
A further feature of the present invention is to provide a capsulectomy apparatus which easily cuts any desired capsular pattern, at any location, and of any size.
Yet further, an additional feature of the present invention is to provide a capsulectomy apparatus which provides a superior foundation for "in-the-bag" lens placement.
Yet another feature of the present invention is to provide a capsulectomy apparatus which minimizes the shear forces associated with capsular tears.
Yet still another feature of the present invention is to provide a capsulectomy apparatus which facilitates a continuous, smooth, curvilinear cut for the anterior capsule.
An additional feature of the present invention is to provide a capsulectomy apparatus which provides a free-flowing anterior capsule button.
Additional features and advantages of the invention will be setforth in part in the description which follows, and in part will become apparent from the description, or may be learned by practice of the invention. The features and advantages of the invention may be realized by means of the combinations and steps particularly pointed out in the appended claims.